Compositions for making substrates, in particular fibrous substrates, such as textiles, oil- and water repellent have been long known in the art. Fluorochemical compounds have been well known as being highly effective in providing oil and water repellency to substrates and in particular textile substrates. For example, the fluorochemical composition may be based on fluorochemical acrylates or methacrylates that are derived from the polymerization of an acrylate or methacrylate monomer that has a fluorinated group and optionally one or more non-fluorinated monomers. Such compositions have been described in for example U.S. Pat. No. 3,660,360, U.S. Pat. No. 5,876,617, U.S. Pat. No. 4,742,140, U.S. Pat. No. 6,121,372 and U.S. Pat. No. 6,126,849 and EP 1 329 548.
Additives have been employed to assist in the oil and water repellency of fluorochemical treating agents. U.S. Pat. No. 4,215,405 teaches that water and oil repellency, which is durable to laundering and dry-cleaning is conferred on fabrics by application of a blend of a fluoroaliphatic vinyl polymer and a carbodiimide.
Fluorochemicals are generally expensive. Therefore, hydrocarbon additives, also called extenders, have been developed in order to reduce cost. Modified synthetic resins, waxes, melamines, paraffin emulsions and similar products have been used as extenders.
U.S. Pat. No. 5,132,028 discloses compositions for imparting water and oil repellency to fabrics such as silk said compositions containing a fluorochemical-type, water and oil repellent agent, a carbodiimide, and at least one component selected from the group consisting of plasticizer, metal alcoholate or ester, zirconium salt, alkylketene dimer, aziridine, and alkenyl succinic anhydride.
EP 0 713 863 discloses carbodiimide compounds obtainable from a reaction mixture comprising an isocyanate compound and a monofunctional alcohol in a non-reactive solvent in the presence of a suitable catalyst, characterized in that the isocyanate compound and the monofunctional alcohol, except for the hydroxy group, are free from isocyanate reactive hydrogen atoms and the monofunctional alcohol is a branched aliphatic alcohol containing at least 8 carbon atoms, and to compositions comprising a fluorochemical oil and water repellent agent and said carbodiimide compound.
Water-based fluorochemical compositions are generally preferred from an environmental point of view. In many commercially available aqueous fluorochemical compositions the fluorochemical compound is dispersed in water with the aid of a surfactant. Such compositions have been found to present problems in certain application methods. In particular, in an application where the fluorochemical composition is applied by contacting the substrate with the composition in a bath and then guiding the substrate through a set of rolls, deposition may occur on the rolls after some time of applying the composition to the substrate. This is undesirable as it will require the application to be interrupted to clean the rolls which adds to the manufacturing cost of a treated substrate. This behavior is further influenced by the nature of the fluorochemical composition as well as the nature of the substrate being treated, some substrates and fluorochemical compositions causing the problem more quickly to occur than others. The problem can be reduced by increasing the amount of surfactant in the composition. However, increasing the surfactant level has been found to adversely affect the repellency performance of the composition.
Accordingly, it would be desirable to reduce or even eliminate the aforementioned problem. Preferably a solution to the problem will be environmentally friendly and cost effective. Preferably, the oil- and/or water repellency properties that can be obtained on a substrate with the composition should not be adversely affected when reducing or eliminating the problem of roll deposit. It would further be desirable to find a new extender in particular an extender that is capable of improving the efficiency of the fluorine treatment in a water-based system. It would further be desirable to provide a composition and a process for conferring both static and especially dynamic water repellency onto fibrous substrates without the aforementioned problems associated with roll deposit.